Quantification of Antifibrillarin (anti-U3 RNP) Antibodies: A New Insight for Patients with Systemic Sclerosis.

BACKGROUND: The detection of additional autoantibodies is of great concern in systemic sclerosis (SSc) when those included in the ACR/EULAR classification are negative. In this context, the interest of antifibrillarin (anti-U3RNP) autoantibodies (AFAs) in the routine evaluation of SSc remains unclear. We aimed to assess the relevance of AFAs and their clinical association in SSc patients. METHODS: In a multicenter observational retrospective study, we collected immunological and clinical data associated with AFA positivity in SSc (n = 42) and non-SSc patients (n = 13). Patients with SSc negative for AFAs (n = 83) were considered as a control group. AFAs were detected by indirect immunofluorescence (IIF) using HEp-2 cells, EliA or immunoblot techniques. RESULTS: We confirmed a typical nuclear IIF pattern and showed that AFAs are mostly exclusive towards SSc conventional autoantibodies. Although also observed in non-SSc patients, high levels of AFAs with the ELiA technique allowed the diagnosis of SSc. Compared to AFA-negative SSc patients, AFA-positive SSc patients more frequently exhibited visceral involvements. They more frequently suffered from the diffuse cutaneous form and had a higher global severity of the disease. CONCLUSIONS: We demonstrate the usefulness of quantifying AFAs in the immunological exploration of SSc, especially when patients are seronegative for SSc conventional autoantibodies and display a typical IIF pattern. AFAs might constitute an interesting marker of SSc severity.

Ethnic influence on the phenotype of French patients with systemic sclerosis.

OBJECTIVE: Systemic sclerosis (SSc) is a rare multisystem autoimmune disorder. It has a worldwide distribution but geographical and ethnic influences are poorly known. METHODS: The aim of the study was to compare demographic characteristics and frequency of internal organ system involvement of Black SSc patients to those of White SSc patients in France. Patient population included 425 SSc patients recruited at Cochin Hospital in Internal medicine and Rheumatology departments. Data were collected at the baseline visit, each Black patient was matched with 2 to 3 White controls from the same department. RESULTS: One hundred and five Black patients and 320 White were included. Demographic comparison highlighted an older age for the White patients (48.66±14.87 vs 39.56±10.79, P<0.0001). Phenotypic comparison showed more severe skin involvement for Black patients: they had more often diffuse skin involvement than White patients (69.2% vs. 44.7%, P<0.0001) with a higher baseline modified Rodnan skin score (15.8 vs. 11.3, P<0.001). Comparisons also showed more active ulcers (46.5% vs. 21.6%, P<0.001) and more common interstitial lung disease (73.7% vs. 43%, P<0.0001) for Black patients. Auto-antibody testing showed that White patients were more likely to harbor anti-centromere antibodies (ACA) (26.6% vs. 9%, P<0.001) whereas Black patients were more likely to have anti-U1RNP antibody (24.6% vs. 6.2%, P<0.0001). CONCLUSION: In this population recruited in a disease referral center, Black patients had more severe skin and lung involvements with lower prevalence of ACA as compared to White patients, supporting a more severe phenotype.

Deep Learning-based Approach for Automated Assessment of Interstitial Lung Disease in Systemic Sclerosis on CT Images.

PURPOSE: To develop a deep learning algorithm for the automatic assessment of the extent of systemic sclerosis (SSc)-related interstitial lung disease (ILD) on chest CT images. MATERIALS AND METHODS: This retrospective study included 208 patients with SSc (median age, 57 years; 167 women) evaluated between January 2009 and October 2017. A multicomponent deep neural network (AtlasNet) was trained on 6888 fully annotated CT images (80% for training and 20% for validation) from 17 patients with no, mild, or severe lung disease. The model was tested on a dataset of 400 images from another 20 patients, independently partially annotated by three radiologist readers. The ILD contours from the three readers and the deep learning neural network were compared by using the Dice similarity coefficient (DSC). The correlation between disease extent obtained from the deep learning algorithm and that obtained by using pulmonary function tests (PFTs) was then evaluated in the remaining 171 patients and in an external validation dataset of 31 patients based on the analysis of all slices of the chest CT scan. The Spearman rank correlation coefficient (ρ) was calculated to evaluate the correlation between disease extent and PFT results. RESULTS: The median DSCs between the readers and the deep learning ILD contours ranged from 0.74 to 0.75, whereas the median DSCs between contours from radiologists ranged from 0.68 to 0.71. The disease extent obtained from the algorithm, by analyzing the whole CT scan, correlated with the diffusion lung capacity for carbon monoxide, total lung capacity, and forced vital capacity (ρ = -0.76, -0.70, and -0.62, respectively; P < .001 for all) in the dataset for the correlation with PFT results. The disease extents correlated with diffusion lung capacity for carbon monoxide, total lung capacity, and forced vital capacity were ρ = -0.65, -0.70, and -0.57, respectively, in the external validation dataset (P < .001 for all). CONCLUSION: The developed algorithm performed similarly to radiologists for disease-extent contouring, which correlated with pulmonary function to assess CT images from patients with SSc-related ILD.Supplemental material is available for this article.© RSNA, 2020.

Corticosteroid-sparing benefit of intravenous immunoglobulin in systemic sclerosis-associated myopathy: A comparative study in 52 patients.

INTRODUCTION: Little is known about systemic sclerosis (SSc)-associated myopathy (SScAM) treatment. Herein we evaluated the use of intravenous immunoglobulin (IVIg) in SScAM. METHODS: We conducted a retrospective study of patients with SScAM in the Internal medicine department of Cochin University Hospital between 1993 and 2017. RESULTS: Fifty-two patients were included comprising 18 (34.6%) with limited SSc and 34 (65.4%) with diffuse SSc. SScAM occurred at a median [interquartile range (IQR)] time of 1 month [0-15] after SSc diagnosis. Thirty-four patients (65.4%) had muscle weakness, 28 (53.8%) had myalgia and 24 (46.2%) had dysphagia. Fifty patients (96.2%) had increased creatine kinase, 22/26 (84.6%) had myopathic electromyography, 10/12 (83.3%) had a high intensity signal of girdle muscles on MRI and 49/50 (98%) had abnormal muscle biopsy. Eighteen (34.6%) patients received IVIg. Severe adverse events occurred in 3/18 (16.7%) patients. When compared to patients who did not receive IVIg, patients who received IVIg had a significantly higher maximal corticosteroid (CS) dose ever, a greater decrease of CS at 3 months, and a lower CS dose at one year and at the end of follow up. CONCLUSIONS: This study suggests the benefit of IVIg as adjunctive therapy, with an acceptable tolerance profile, and supports its use as a CS-sparing agent, in SScAM.